【推荐1】Causes of sandstorms

In desert areas, sandstorms are most commonly caused by either thunderstorm outflows, or by strong pressure gradients（气压梯度）which cause an increase in wind speed over a wide area. In some cases, dust and sand may set a limit to a shallow depth by a low-lying temperature change.     1     Drought is another cause of sand storms. Poor farming practices make dust and sand free of protection from the wind.     2     A sandstorm can transport and carry large amounts of sand. Desert is the key source of sandstorms. Saharan sandstorms have increased abut 10 times during the half century since the 1950’s, causing topsoil loss in nearby countries. In Mauritania, there were just two sandstorms a year in the early 1960’s, but there are 80 a year today.    3    

Sand storms have also been shown to increase the spread of disease across the globe. Virus in the dust is blown into the atmosphere by the storms. Some diseases may not be urgent at the very beginning, but they can develop into deadly ones if left untreated.     4    

Sandstorms cause soil loss from the dry lands, doing harm to agriculture. Sandstorms also reduce visibility, affecting airplanes and road transportation.     5    

Dust can also have good effects. Central and South American rainforests get most of their mineral nutrients from the Sahara; iron-poor ocean regions get iron.

【推荐2】The Pacific island of Tonga was struck by huge volcanic explosion on January 15, 2022, which was followed by a tsunami (海啸) that flooded the regions of the capital, Nuku’alofa. Witnesses reported ash was falling over the capital, and social media images showed water flooding into a church and many residences. Local residents had to flee to higher ground when the tsunami warning was issued.

The capital of Tonga is around 65 kilometers north of the volcano. The volcano’s plumes of gas, smoke, and ash extended 20 kilometers into the sky, according to Tonga Geological Services. According to authorities in Suva, the eight-minute eruption was so powerful that it could be heard as “loud thunder sounds” more than 500 miles away. Storm waves have been predicted in New Zealand, which is more than 2,300 kilometers away from Tonga.

Internet and phone lines went down after the violent volcanic eruption, leaving the 105,000 residents on the islands almost uncontactable. All communication to the outside world in Tonga was affected due to damage to the undersea cable (电缆). Digicel, a Jamaican phone company that partly owns the Tonga Cable System, said that it might take 24 hours to restore the important communications link before it could provide an update on work. The company said it was working urgently with local authorities to “resolve the damage”, adding that its domestic (国内的) mobile phone towers were operating across the main island of Tongatapu.

New Zealand Prime Minister Jacinda Ardern said that the New Zealand government has made an initial sum of 340,000 dollars available to provide assistance to Tonga. An Australian Air Force P8 Poseidon aircraft also reached Tonga on January 17. Meanwhile, Chinese Foreign Ministry spokesperson said that China is closely watching the volcanic eruptions and the disasters including tsunami and volcanic ash in Tonga, and stands ready to provide every possible support and assistance at Tonga’s request.

【推荐3】Mountain regions are not just playgrounds for the richer citizens on the planet, however. The disappearing snows of Mount Kilimanjaro are a worrying sign that nowhere is safe from the adverse effects of human actions. The United Nations has identified three main areas that need to be addressed to ensure the future safety of the world’s mountains. These are: the protection of mountain ecosystems, the encouragement of peace and stability in mountain regions, and assistance for mountain people to maintain their ways of life.

From the busy cities of India to the farmlands of California, more than half the world’s population is dependent on mountains for their fresh water supply. Global warming, deforestation, mining and heavy farming seriously damage breakable mountain ecosystems and put vital fresh water sources at risk.

Mountain regions host a large proportion of the world’s wars. From Afghanistan to the Balkans and the Andes to many parts of Africa, territorial(领土的) and drug related conflicts have damaging effects on the local environment and the lives of the local people. Fighting makes essential tasks such as farming impossible. Land mines make large areas of potential farming ground unusable. Also schools, roads, bridges and other important infrastructure(基础设施) are left in ruins.

Mountain people are among the poorest, least represented groups on the earth. They face many hardships and each day can be, “a test of survival”. Damage to mountain ecosystems worsens their situation and leaves them even more unprotected to disease and ‘natural’ disasters such as floods and landslides. It’s been recommended that forest profit should be reinvested in mountain communities and the people living there should be given a stronger political voice. Their fate is in many ways directly connected with that of people living at sea level.

There is an old motto for visitors to the countryside which advises them to leave nothing but footprints. It is still as relevant today as it always was. Unfortunately, the size of our footprints seems to be getting larger.